JP2002370458A - Image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming material having a wide application range and capable of forming an image with a high sensitivity by a heat generated by an exposure, heating or photothermal conversion, obtaining the image having a high resolution and a high sharpness irrespective of an area of the image forming material and directly forming an image based on digital data by operating an infrared laser or the like. SOLUTION: The image forming material comprises an image recording layer made of a polymer compound having a structure having a functional group having hydrophilic/hydrophobic properties changable by a heat, an acid or a radiation on a support and capable of bonding by a direct chemical bond on the support. In this material, the hydrophilic/hydrophobic properties of the surface of the image recording layer are changed by supplying the heat or the acid or by irradiating with the radiation, and organic or inorganic molecules capable of forming a visible image are adsorbed to a region in which the hydrophilic/hydrophobic properties are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material, and more particularly to an image forming material which can easily form an image having excellent resolution and is useful as a display material and a pattern forming material.

[0002]

2. Description of the Related Art Conventionally, various image forming materials have been used as display materials and pattern forming materials. These are usually used to image-wise attach a colored material such as ink to a white image-receiving material surface such as a paper medium, or to image-wise adhere a light-impermeable material such as a pigment to a transparent image-receiving material such as a plastic film. By doing so, image formation is performed.
Image formation, for example, by attaching ink to the image receiving material by inkjet printing, or, as typified by a copying machine, electrostatically attaching a colored material to the surface of the image receiving material, and heat-fixing the heat-sensitive recording material. The method is carried out by various methods such as using a dye to form a color of a dye precursor by heating. As a method for forming a dense pattern with controlled orientation, for example, Japanese Patent Application Laid-Open No. 2000-247799 proposes a method for producing a functional organic molecular thin film.
According to this method, a dense pattern can be formed, but for imagewise writing, UV exposure is performed through a mask such as a lithographic film, as in the conventional image forming method of a lithographic printing plate precursor. Therefore, the process is complicated as an image forming method. Further, in a conventional general image forming method, a high-resolution image is formed on a large-area image receiving material,
It has been difficult to form a high density image on a thin film image receiving material.

On the other hand, recently, as an image forming material, a method of directly forming an image on an image receiving material from digitized image data without using a media such as a lith film has attracted attention and various proposals have been made. If such a digitized image forming method is used, a clear image is expected to be formed regardless of the area and characteristics of the image receiving material. At present, a technique for stably fixing a light-impermeable material or a colored material based on the above has not been established yet.

[0004]

SUMMARY OF THE INVENTION An object of the present invention, which has been made in view of the above-mentioned disadvantages of the prior art, is that an image can be formed with high sensitivity by exposure or heating, regardless of the area of the image forming material. Another object of the present invention is to provide an image forming material having a wide range of applications that can obtain a high-resolution, high-sharpness image and can directly form an image based on digital data by operating an infrared laser or the like.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be achieved by applying a polymer compound whose surface characteristics are changed by exposure, heating, and irradiation of an infrared laser. And completed the present invention. That is, the image forming material of the present invention, on a support,
An image recording layer comprising a polymer compound having a functional group whose hydrophilicity / hydrophobicity is changed by heat, acid or radiation, and having a structure capable of being directly bonded to the support by a chemical bond, The method further comprises heating, supplying an acid, or irradiating radiation to change the hydrophilicity / hydrophobicity of the surface of the image recording layer, and adsorb organic or inorganic molecules in the region where the hydrophilicity / hydrophobicity has changed. Here, the heat used for the image recording layer,
A polymer compound having a functional group whose hydrophilicity / hydrophobicity is changed by an acid or radiation and having a structure capable of being directly bonded to the support by a chemical bond is provided on the support by direct chemical bond at the end of a polymer chain. A linear polymer bound to the body surface, or a linear polymer bound to the support surface by a chemical bond at the end of the polymer chain via a stem polymer A preferred embodiment is a compound. Further, as the light-impermeable material and the colored material for forming a visible image, those selected from organic or inorganic dyes and pigments are preferable from the viewpoint of easy availability.

The image forming material of the present invention has
Depending on the polarity of the surface of the polymer compound having a functional group whose hydrophilicity / hydrophobicity changes due to heat, acid or radiation (hereinafter, appropriately referred to as a polarity conversion group), a radiation irradiation region including exposure and a heating region are selected. Since an image is formed by adsorbing organic or inorganic molecules, a high-resolution image based on digital data can be obtained regardless of the area of the image forming material. The polymer compound having a polarity conversion group used as an image recording layer of an image forming material is, for example, bonded to a support directly at its end or via a trunk polymer compound, and further to form a visible pattern. The organic or inorganic molecules are strongly ionically adsorbed on the recording layer surface in accordance with the polarity, so that both the image area and the non-image area exhibit high strength and abrasion resistance. as a result,
Even with a thin layer, high-strength image formation is possible, and when a dye is used as an organic molecule or various pigments are used as an inorganic molecule, the dye is ionically adsorbed to a polarity conversion group,
Since the adsorbed molecules are firmly fixed in a state close to a monomolecular film, it is considered that an image having high density and excellent sharpness can be formed even in a thin layer. Further, in the present invention, the polarity conversion group having an ability to adsorb organic or inorganic molecules,
Due to the high mobility of the grafted chain structure, the adsorption speed is extremely fast and the amount of molecules that can be adsorbed per unit area is large compared to the adsorption of molecules by a general crosslinked polymer membrane. . In the image forming material of the present invention,
While maintaining the image quality, the image recording layer can be thinned to achieve higher sensitivity, and the polymer compound constituting the image recording layer is directly chemically bonded to the support (image receiving material). Therefore, there is an advantage that even a thin layer has excellent durability.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the image forming material of the present invention will be described in detail. A feature of the image forming material of the present invention is to form an image recording layer in which the terminal of a polymer chain having a functional group whose hydrophilicity / hydrophobicity changes is chemically bonded directly or via a backbone polymer to the surface of a support. Will be described. [Surface Graft Polymerization] The image recording layer according to the present invention is prepared by using a means generally called surface graft polymerization. Graft polymerization is a method of synthesizing a graft (grafted) polymer by providing an active species on a polymer compound chain, thereby further polymerizing another monomer that initiates polymerization,
In particular, when a polymer compound that gives an active species forms a solid surface, it is called surface graft polymerization.

As the surface graft polymerization method for realizing the present invention, any known methods described in the literature can be used. For example, New Polymer Experimental Science 10, edited by The Society of Polymer Science, 1994, published by Kyoritsu Shuppan Co., Ltd., P135 describes a photograft polymerization method and a plasma irradiation graft polymerization method as surface graft polymerization methods. Also, Adsorption Technology Handbook, NTS Co., Ltd., supervised by Takeuchi, published on 1999.2.
p203 and p695 describe a radiation-induced graft polymerization method such as γ-ray and electron beam. As a specific method of the photograft polymerization method, the methods described in JP-A-10-296895 and JP-A-11-119413 can be used.

As means for preparing a surface graft layer in which the terminal of the polymer compound chain is directly chemically bonded, other than these, trialkoxysilyl group, isocyanate group, amino group, , A reactive functional group such as a hydroxyl group or a carboxyl group, and a coupling reaction between the reactive functional group and a functional group present on the surface of the support. In addition, the support surface in the present invention refers to a surface having a function in which the terminal of the polymer compound having a polarity conversion group is chemically bonded directly or via a stem polymer compound, The support itself may have such surface characteristics, or an intermediate layer may be separately provided on the support, and the intermediate layer may have such characteristics.

As a means for preparing a surface in which the ends of the polymer compound chain having a polarity conversion group are chemically bonded via a trunk polymer compound, a coupling reaction with a support surface functional group is carried out. A functional polymer is added to the side chain of the stem polymer, and a graft polymer compound incorporating a polymer compound chain having a functional group whose hydrophobicity changes as a graft chain is synthesized. It can also be formed by a coupling reaction with a group.

[Functional group whose hydrophilicity / hydrophobicity changes] Next, one of the features of the lithographic printing plate precursor according to the present invention, a functional group whose hydrophilicity / hydrophobicity changes due to heat, acid or radiation (polar conversion group). Will be described. As the polarity conversion group, there are two types of a functional group that changes from hydrophobic to hydrophilic and a functional group that changes from hydrophilic to hydrophobic.

(Functional group that changes from hydrophobic to hydrophilic) Examples of the functional group that changes from hydrophobic to hydrophilic include well-known functional groups described in the literature. Useful examples of these functional groups include alkyl sulfonic acid esters, disulfones, sulfonimides described in JP-A-10-282672, alkoxyalkyl esters described in EP 0 652 483, WO 92/9934, and H.I. Ito et al., Macror
Examples include t-butyl esters described in Nolecules, vol. 21, pp. 1477, and carboxylic acid esters protected with an acid-decomposable group described in literatures such as silyl esters and vinyl esters.

Also, Masahiro Kadooka, "Surface" vol.133 (199)
5), iminosulfonate group described in pp. 374, written by Masahiro Kadooka,
Polymer preprints, Japan vol. 46 (1997), pp. 2045 described β ketone sulfonic acid esters, Ao Yamaoka, Japanese Patent Application Laid-Open No. 63-257750, nitrobenzyl sulfonate compounds can also be mentioned. It is not limited to. Of these, the particularly excellent are the secondary alkylsulfonic acid ester groups shown below,
Carboxylic acid ester groups and alkoxyalkyl ester groups shown below.

In the present invention, the secondary alkylsulfonic acid ester group which is particularly excellent as a functional group that changes from hydrophobic to hydrophilic is represented by the following general formula (1).

[0015]

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(In the general formula (1), L represents an organic group comprising a polyvalent nonmetallic atom necessary for linking to the polymer skeleton, and R ¹ and R ² represent a substituted or unsubstituted alkyl group. R ¹ and R ² may form a ring together with the secondary carbon atom (CH) to which they are attached.)

In the general formula (1), R ¹ and R ² represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and R ¹ and R ² represent a secondary carbon atom to which they are bonded ( CH) to form a ring. When R ¹ and R ² represent a substituted or unsubstituted alkyl group, examples of the alkyl group include a linear, branched or cyclic alkyl group such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, and a cyclohexyl group. Those having 1 to 25 carbon atoms are preferably used. When R ¹ and R ² represent a substituted or unsubstituted aryl group, the aryl group includes a carbocyclic aryl group and a heterocyclic aryl group. As the carbocyclic aryl group, those having 6 to 19 carbon atoms such as a phenyl group, a naphthyl group, an anthracenyl group and a pyrenyl group are used. Examples of the heterocyclic aryl group include those having 3 to 20 carbon atoms and 1 to 5 heteroatoms such as a pyridyl group, a furyl group, and a quinolyl group, a benzofuryl group, a thioxanthone group, and a carbazole group in which a benzene ring is fused. Is used.

When R ¹ and R ² are a substituted alkyl group or a substituted aryl group, examples of the substituent include an alkoxy group having 1 to 10 carbon atoms such as a methoxy group and an ethoxy group, a fluorine atom, a chlorine atom and a bromine atom. A halogen atom, a trifluoromethyl group, a halogen-substituted alkyl group such as a trichloromethyl group, a methoxycarbonyl group, an ethoxycarbonyl group, a t-butyloxycarbonyl group, a p-chlorophenyloxycarbonyl or the like having 2 to 15 carbon atoms.
A hydroxyl group; an acyloxy group such as acetyloxy, benzoyloxy, p-diphenylaminobenzoyloxy; a carbonate group such as a t-butyloxycarbonyloxy group; a t-butyloxycarbonylmethyloxy group A substituted or unsubstituted amino group such as an amino group, a dimethylamino group, a diphenylamino group, a morpholino group, or an acetylamino group; a thioether group such as a methylthio group or a phenylthio group; a vinyl group; Alkenyl groups such as steryl group; nitro group; cyano group; acyl groups such as formyl group, acetyl group and benzoyl group; aryl groups such as phenyl group and naphthyl group; heteroaryl groups such as pyridyl group. Can . When R ¹ and R ² are a substituted aryl group, as the substituent, an alkyl group such as a methyl group or an ethyl group can be used in addition to those described above.

As the above R ¹ and R ² , a substituted or unsubstituted alkyl group is preferable from the viewpoint of excellent storage stability of the light-sensitive material, and an alkoxy group, a carbonyl group,
An alkyl group substituted with an electron-withdrawing group such as an alkoxycarbonyl group, a cyano group, or a halogen group, or an alkyl group such as a cyclohexyl group or a norbornyl group is particularly preferable. As the physical properties, the chemical shift of secondary methine hydrogen in proton NMR in deuterated chloroform was 4.
Compounds that appear in a lower magnetic field than 4 ppm are preferred.
Compounds that appear in a lower magnetic field than 6 ppm are more preferred.
As described above, the alkyl group substituted with an electron-withdrawing group is particularly preferable because a carbocation which is considered to be generated as an intermediate during the thermal decomposition reaction is destabilized by the electron-withdrawing group and decomposition is suppressed. It is thought to be because.
Specifically, as the structure of —CHR ¹ R ^2, a structure represented by the following formula is particularly preferable.

[0020]

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The polyvalent linking group comprising a non-metallic atom represented by L in the above general formula (1) includes 1 to 60 carbon atoms, 0 to 10 nitrogen atoms, From 50 to 50 oxygen atoms, from 1 to 100 hydrogen atoms, and from 0 to 20 sulfur atoms. More specific linking groups include those constituted by combining the following structural units.

[0022]

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When the polyvalent linking group has a substituent, examples of the substituent include an alkyl group having 1 to 20 carbon atoms such as a methyl group and an ethyl group, and a carbon atom having 6 carbon atoms such as a phenyl group and a naphthyl group.
To 16 aryl groups, hydroxyl groups, carboxyl groups,
C1-C6 acyloxy groups such as sulfonamide groups, N-sulfonylamido groups, and acetoxy groups; C1-C6 alkoxy groups such as methoxy groups and ethoxy groups; halogens such as chlorine and bromine. An atom, a methoxycarbonyl group, an ethoxycarbonyl group, an alkoxycarbonyl group having 2 to 7 carbon atoms such as a cyclohexyloxycarbonyl group, a cyano group, a carbonate group such as t-butyl carbonate, or the like can be used.

In the present invention, an alkoxyalkyl ester group which is particularly excellent as a functional group that changes from hydrophobic to hydrophilic is represented by the following general formula (2).

[0025]

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In the formula, R ³ represents a hydrogen atom, R ⁴ represents a hydrogen atom or an alkyl group having 18 or less carbon atoms, and R ⁵ represents an alkyl group having 18 or less carbon atoms. Further, two of R ³ , R ⁴ and R ⁵ may be combined to form an interval. In particular, it is preferable that R ⁴ and R ⁵ combine to form a 5- or 6-membered ring.

As described above, as the functional group that changes from hydrophobic to hydrophilic in the present invention, a secondary alkylsulfonic acid ester group represented by the general formula (1) is particularly preferable. Functional group represented by the general formulas (1) and (2) [functional group (1)
To (13)] are shown below.

[0028]

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[0029]

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(Functional Group Changing from Hydrophilic to Hydrophobic) In the present invention, as the functional group changing from hydrophilic to hydrophobic by heat, acid or radiation, known functional groups, for example, JP-A No. No. 296895 and US Pat. No. 6,1
No. 90,830, a polymer containing an onium base;
Particularly, a polymer containing an ammonium salt can be mentioned. Specific examples thereof include (meth) acryloloxyalkyltrimethylammonium. In addition, a carboxylic acid group and a carboxylic acid group represented by the following general formula (3) are preferred.
It is not particularly limited to these examples.

[0031]

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(Wherein X is -O-, -S-, -Se-,
^{-NR 8 -, - CO -,} - SO -, - SO 2 -, - PO
^{-, - SiR 8 R 9 -} , - CS- represents, R ^6, R ^7,
R ⁸ and R ⁹ each independently represent a monovalent group, and M represents a positively charged ion. ) Specific examples of R ⁶ , R ⁷ , R ⁸ , and R ⁹ include -F, -Cl,
^{-Br, -I, -CN, -R 10} , -OR 10, -OCOR
^{10, -OCOOR 10, -OCONR 10 R} 11, -OSO 2
R ¹⁰ , —COR ¹⁰ , —COOR ¹⁰ , —CONR ¹⁰ R ¹⁴ ,
^{-NR 10 R 11, -NR 10 -COR} 11, -NR 10 -COO
R ¹¹ , -NR ¹⁰ -CONR ¹¹ R ¹² , -SR ¹⁰ , -SOR
_{^{10, -SO 2 R 10, -SO}} 3 R 10 , and the like. R ¹⁰ ,
R ¹¹ and R ¹² each represent a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or an alkynyl group.

Of these, preferred as R ⁶ , R ⁷ , R ⁸ and R ⁹ are specifically a hydrogen atom, an alkyl group, an aryl group, an alkynyl group and an alkenyl group. Specific examples of M include an ion having a positive charge as described above. Specific examples of the functional group represented by the general formula (3) [functional groups (14) to (31)] are shown below.

[0034]

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[0035]

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The polymer compound having a polarity conversion group in the present invention may be a homopolymer of one kind of monomer having a functional group as described above, or a copolymer of two or more kinds of monomers. Further, a copolymer with another monomer may be used as long as the effects of the present invention are not impaired. Specific examples of the monomer having a functional group as described above are shown below. (Specific examples of the monomer having a functional group represented by the general formulas (1) and (2) [exemplified monomers (M-1) to (M-1
5)])

[0037]

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[0038]

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(Specific examples of the monomer having a functional group represented by the general formula (3) [exemplified monomers (M-16) to
(M-33)])

[0040]

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[0041]

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[Support Surface] The image-forming material of the present invention comprises:
The surface graft layer in which the terminal of the above-mentioned polymer compound having a polarity conversion group is chemically bonded directly or through a stem polymer compound, and the terminal of the polymer compound is directly or chemically formed through the stem polymer compound. It has a support surface capable of binding. As described above, the surface of the support itself may have such characteristics, and an intermediate layer having such characteristics may be provided on the surface of the support.

(Surface of Support or Intermediate Layer) The surface of such a support may be either an inorganic layer or an organic layer as long as it has characteristics suitable for providing the surface graft layer by graft synthesis. . In the present invention, since the change in hydrophilicity / hydrophobicity is exhibited by the image forming layer made of a thin polymer compound, the polarity of the surface is not a problem, and the surface may be hydrophilic or hydrophobic. Such an intermediate layer is preferably a layer having an organic surface, particularly when the thin-layer polymer of the present invention is synthesized by a photograft polymerization method, a plasma irradiation graft polymerization method, or a radiation irradiation graft polymerization method. It is particularly preferable to use an organic polymer layer. As organic polymers, epoxy resins, acrylic resins, urethane resins, phenolic resins, styrene resins, vinyl resins, polyester resins, polyamide resins, melamine resins, synthetic resins such as formalin resins, gelatin, casein, cellulose, Any of natural resins such as starch can be used.However, in the case of photografting polymerization, plasma irradiation graft polymerization, irradiation irradiation graft polymerization, etc., the initiation of graft polymerization proceeds from the extraction of hydrogen from the organic polymer. Polymers, especially acrylic resins, urethane resins,
It is possible to use styrene resin, vinyl resin, polyester resin, polyamide resin, epoxy resin, etc.
It is particularly preferable from the viewpoint of production suitability. Such an intermediate layer may also serve as a substrate (support) described later, or may be an intermediate layer provided on the support as needed.

Further, in the image forming material of the present invention,
From the viewpoints of the formability of the image forming layer and the adhesion to the image recording layer, a support having a roughened surface may be used as the support to which the polymer compound is directly chemically bonded. When a roughened support is used, it is preferable that the surface properties satisfy the following conditions.
As a preferable state of the roughened support, the center line average roughness (Ra) of the two-dimensional roughness parameter is 0.1 to 1 μm.
m, the maximum height (Ry) is 1 to 10 μm, the ten-point average roughness (Rz) is 1 to 10 μm, and the average interval of unevenness (Sm) is 5
~ 80μm, average distance (S) between local peaks is 5 ~ 80μ
m, the maximum height (Rt) is 1 to 10 μm, the center line peak height (Rp) is 1 to 10 μm, and the center line valley depth (Rv) is 1 to
Those having a range of 10 μm are preferred, and those satisfying one or more of these conditions are preferable, and it is more preferable that all of them are satisfied.

(Light-to-heat conversion material) When the image-forming material of the present invention is image-recorded with an IR laser or the like, a light-to-heat conversion material for converting the light energy into heat energy is provided somewhere in the image-forming material. It is preferable to contain them. The portion containing the light-to-heat conversion material may be, for example, any of an image recording layer, an intermediate layer, and a support substrate, and further, a light-to-heat conversion layer is provided between the intermediate layer and the support substrate. May be added.

As the photothermal conversion material that can be used in the image forming material of the present invention, any material can be used as long as it can absorb light such as ultraviolet light, visible light, infrared light and white light and convert it into heat. , Carbon graphite, pigments, phthalocyanine pigments, iron powder, graphite powder, iron oxide powder, lead oxide, silver oxide, chromium oxide, iron sulfide, chromium sulfide, and the like. Particularly preferred in the present invention are dyes, pigments or fine metal particles having a maximum absorption wavelength in the range of 760 nm to 1200 nm, which is the exposure wavelength of an infrared laser used for writing.

As the dye, commercially available dyes and known dyes described in literatures (for example, "Dye Handbook" edited by The Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, and metal thiolate complexes. Preferred dyes include, for example, JP-A-58-125246.
JP-A-59-84356, JP-A-59-2028
29, JP-A-60-78787, JP-A-58-173696 and JP-A-5-173696.
Methine dyes described in JP-A-8-181690 and JP-A-58-194595;
JP-A-58-224793, JP-A-59-481
No. 87, JP-A-59-73996, JP-A-60-52
No. 940, JP-A-60-63744 and the like, naphthoquinone dyes described in JP-A-58-112792 and the like, British Patent 434
No. 875, and the like.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924 is also preferable. JP-A-57-142645 (U.S. Pat. No. 4,327,169);
Nos. 8-220143, 59-41363 and 59-
No. 84248, No. 59-84249, No. 59-146
Nos. 063 and 59-146061; cyanine dyes described in JP-A-59-216146; pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475; Fairness 5-135
Nos. 14 and 5-19702 are also preferably used. Further, as another preferable example of the dye, a near-infrared absorbing dye described as formulas (I) and (II) in U.S. Pat. No. 4,756,993 can be exemplified. Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes.

The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
Can be used. As the type of pigment, black pigment, yellow pigment, orange pigment, brown pigment,
Red pigment, purple pigment, blue pigment, green pigment, fluorescent pigment,
Metal powder pigments and other polymer-bound dyes can be used.
Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Preferred among these pigments is carbon black.

These dyes or pigments are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 50% by weight, based on the total solid content of the layer containing the photothermal conversion material.
1 to 10% by weight, particularly preferably 0.5 to 1 in the case of dyes
0% by weight, and in the case of a pigment, particularly preferably 3.1 to 10% by weight. If the amount of the pigment or dye is less than 0.01% by weight, the sensitivity becomes low, and if it exceeds 50% by weight, the film strength of the photothermal conversion material-containing layer becomes weak.

(Support Substrate) A support (substrate) which is used in the image forming material of the present invention and has a support surface having the above characteristics on its surface may be a dimensionally stable plate-like material. Preferably, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, propion) Cellulose, butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or vapor-deposited. As the support used in the present invention, a polyester film or an aluminum plate is preferable, and among them,
A polyester film that can also serve as the lower layer is particularly preferable. The aluminum plate used as the base material may be subjected to a known surface treatment such as a surface roughening treatment or an anodic oxidation treatment as necessary.

In the case of using a plastic film such as a polyester film, which is another preferred embodiment, a film which has been subjected to the above-mentioned roughening treatment is used for the purpose of improving the formability and adhesion of the hydrophilic surface. be able to.

When the support used for the image forming material of the present invention also serves as the intermediate layer, the film itself made of the resin material described in detail for the intermediate layer can be used. As described above, the surface of the support to which the polymer compound constituting the image recording layer is directly chemically bonded is preferably roughened.

[Image Forming Method] Next, an image forming method of the image forming material according to the present invention thus obtained will be described. In the image forming mechanism of the image forming material of the present invention, the polarity conversion group of the polymer compound in the image recording layer undergoes a polarity conversion in a heating or radiation irradiation region, and has a positive or negative charge. By adsorbing organic or inorganic molecules in this area, the area becomes an image area,
In the non-heated area or the non-irradiated area, the hydrophilic layer remains as it is, and the organic or inorganic molecules are not adsorbed and become the non-image area.
In addition, a hydrophilic substance, for example, a water-soluble dye is adsorbed on a hydrophilic region obtained by polarity conversion, or a hydrophobic substance, for example, a lipophilic dye is adsorbed on a hydrophobic region to form an image. You can also.

(Writing) Writing of an image to the image forming material of the present invention is performed by irradiation with radiation such as light or heating. In addition, as one mode of light irradiation, an image can be formed by heating by scanning exposure with laser light or the like in an infrared region as long as the photothermal conversion material is used in combination. Methods used for image formation include heating,
A method of performing writing by radiation irradiation such as exposure may be used. For example, irradiation with light using an infrared laser, an ultraviolet lamp, visible light, or the like, irradiation with an electron beam such as γ-ray, thermal recording using a thermal head, and the like are possible. Examples of these light sources include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Radiation includes electron beam, X-ray, ion beam,
There are far infrared rays. G-line, i-line, Deep-UV
Light, high-density energy beams (laser beams) are also used. Specific examples generally used include preferably direct image-like recording using a thermal recording head or the like, scanning exposure using an infrared laser, high illuminance flash exposure such as a xenon discharge lamp, or infrared lamp exposure. In order to form a direct image by digital data of a computer, a method of causing polarity conversion by laser exposure is preferable. Examples of the laser include a gas laser such as a carbon dioxide laser, a nitrogen laser, an Ar laser, a He / Ne laser, a He / Cd laser, and a Kr laser, a solid laser such as a liquid (dye) laser, a ruby laser, and an Nd / YAG laser; Semiconductor lasers such as GaAlAs, InGaAs lasers, KrF lasers, XeCl lasers, XeFs
A laser, an excimer laser such as Ar ₂ or the like can be used. Of these, exposure with a solid-state high-output infrared laser such as a semiconductor laser that emits infrared light having a wavelength of 700 to 1200 nm or a YAG laser is preferable.

(Organic or Inorganic Molecule) Here, the organic or inorganic molecule to be adsorbed on the polarity-converted surface is a low-molecular compound or a high-molecular compound as long as it can form a visible image. Is also good. Note that a visible image can be formed refers to a substance having absorption in a visible wavelength region, and specifically includes, for example, colored dyes or pigments, various light-impermeable pigments, and fine metal particles. Can be

(Relationship between Polarity of Surface Graft Polymerization and Organic or Inorganic Molecule) It has an anion graft polarity conversion functional group such as an alkylsulfonic acid ester group represented by the general formula (1) specifically exemplified above. In the image recording layer, only the exposed area selectively has a negative charge, and a visible image is formed by adsorbing a molecule having a positive charge, for example, a cationic dye. When such an image forming mechanism is used, since only the exposed portion has the polarity conversion by having the polarity conversion, not only a single color image but also a multicolor image can be formed. That is, the image forming material is exposed to light, a cationic dye having a yellow color tone is adsorbed on the exposed area, and excess dye is removed by washing with water to form a yellow image. At this time, since the polarity conversion group in the unexposed portion is not affected, the same image forming material is again subjected to imagewise exposure to cause polarity conversion, and the cation having a magenta color tone in the exposed area. A multi-color image can be formed by stepwise imagewise exposure, such as forming a magenta image by adsorbing a dye and then forming a cyan image in the same manner.

Examples of the cationic organic or inorganic molecules that can be used for image formation include cationic dyes, cationically charged inorganic pigments, metal fine particles, and coated pigments having a cationic surface layer formed on the surface. And coated metal fine particles. Here, as the cationic dye that can be used, a known dye can be appropriately selected and used according to the purpose such as color tone and image density. Such a cationic dye is electrically attracted to the surface of the image recording layer by the function of the acidic group (sulfonic acid group, carboxylic acid group, etc.) which is the above-mentioned polarity conversion group, and penetrates not only on the surface but also inside, and finally, It is considered that an image is formed by bonding to an acidic group. Because this image is due to ionic interactions,
It is strongly adsorbed, and a high density image with high fastness is formed with a small amount of dye.

Examples of the cationic dye include a dye having an alkylamino or aralkylamino bond at a terminal of a chromophore, a dye having an acid amide bond such as a sulfonate alkylamide bond, an azo dye having a group capable of forming a cation, and a methine dye. And heterocyclic compounds such as thiazole / azo dyes. Examples of the skeleton of the cationic dye include triphenylmethane, diphenylmethane, xanthene, acridine, azine, thiazine, thiazole, oxazine, azo, and the like. Examples of such a dye are “New Dye Chemistry” written by Yutaka Hosoda, Gihodo, ( 316th of 1957)
Pp. 322-322.

As another image forming mechanism, for example, in an image recording layer having a cation-graft polarity conversion functional group such as an ammonium group described in JP-A-10-296895, the surface of the original recording layer material has a positive charge. And only the exposed area loses the charge. When a molecule having a negative charge, for example, an acid dye or the like is adsorbed here, the acid dye is adsorbed on the unexposed portion to form a visible image. When using such an image forming mechanism,
Since organic or inorganic molecules are adsorbed only on the unexposed portions, an image forming material suitable for forming a monochromatic image can be obtained.

Examples of the anionic organic or inorganic molecules that can be used for image formation include acid dyes, anionic charged inorganic pigments, metal fine particles, and coated pigments having an anionic surface layer formed on the surface. And coated metal fine particles. Here, as the acid dye that can be used,
Known dyes can be appropriately selected and used according to the purpose such as color tone and image density. Examples of such acid dyes include azo-based, anthraquinone-based, triphenylmethane-based, xanthene-based, azine, and phosphorus-based dyes, and any of these can be used arbitrarily.
Specifically, for example, CIAcid Yellow 1, CIAcid O
range 33, CIAcid Red 80, CIAcid Violet 7, C.
I. Acid Blue 93, and such a dye is described in, for example, "Dye Handbook" edited by Organic Synthetic Chemistry Association, Maruzen, (197
0), pp. 392-471.

When charged fine particles are used,
The central part of the fine particles called a core may be either an inorganic substance or an organic substance. When the core is an inorganic substance, preferably, gold,
Noble metal particles such as silver, palladium, rhodium and platinum. When the core is an organic substance, it is preferably an organic polymer. The particle size of the charged fine particles is preferably in the range of 0.1 nm to 1000 nm, and more preferably in the range of 1 nm to 100 nm. When the particle size is smaller than 0.1 nm, the handleability is poor. When the particle size is larger than 1000 nm, the strength of the formed image tends to deteriorate because the contact area for ionically bonding with the polarity-converted functional group is reduced. There is. In addition, when a transparent support such as glass or a transparent plastic film is used, from the viewpoint of securing light transmittance and visibility, preferably from 0.2 to 100 nm, more preferably from 1 to 10 nm. Use something.

The fine particles having a high-density charged surface can be obtained, for example, by the method of Toru Yonezawa et al., Ie, T. Yonezawa, Chemis
try Letters., 1999 page1061, T.Yonezawa, Langumuir
2000, vol16, 5218 and Toru Yonezawa, Polymer preprint
s, Japan vol.49. 2911 (2000). Yonezawa et al. Have shown that a metal-sulfur bond can be used to chemically modify the surface of a metal particle with a charged functional group at a high density.

The organic or inorganic molecule is not limited to one kind,
If necessary, a plurality of types can be used in combination. Further, in order to obtain a desired color tone, a plurality of materials can be mixed and used in advance. As a method of adsorbing the organic or inorganic molecules on the portion where the polarity has been converted, a solution in which the organic or inorganic molecules having a charge on the surface is dissolved or dispersed is coated on the surface of the substrate whose polarity has been imagewise changed by exposure or the like. And a method of immersing the surface of the support image-converted in polarity in these solutions or dispersions. In either case of coating or dipping, an excessive amount of organic or inorganic molecules is supplied, and sufficient introduction of ionic bonds between the polar conversion groups is performed. The contact time is preferably about 10 seconds to 60 minutes, more preferably about 1 minute to 20 minutes.
It is preferable that the organic or inorganic molecule be bonded in a maximum amount capable of adsorbing to the polarity-converted region of the support surface in terms of image sharpness, color tone and durability. From the efficiency of adsorption, the concentration of the solution or dispersion is at least 10 to 20.
% By weight is preferred.

The amount of these organic or inorganic molecules to be used can be appropriately selected depending on the image forming mechanism of the image forming material, but is introduced by ionic adsorption, and is introduced almost in the state of a monomolecular film. Compared to the amount of color forming materials and colored materials used for general image forming materials,
An image with high density and high sharpness can be formed. In addition, using a resin film having the above surface properties on the support, when a light-impermeable material such as an inorganic pigment or a metal pigment is adsorbed, or a light-transmitted colored dye is adsorbed. In this case, it is possible to easily obtain a light-transmissive pattern forming material such as an OHP or an electric lamp on the street, or a display material.

The image forming material of the present invention on which an image has been formed by the above method is expected to be widely used as various pattern forming materials or display materials.

[0067]

[Example 1]

(Preparation of image forming material: pattern forming material) 188 μm
Using a corona-treated polyethylene terephthalate film as a support, the following composition was applied to the surface of the support using a coating bar of a rod No. 10, dried at 100 ° C. for 1 minute, and absorbed at a thickness of 1.6 μm. An intermediate layer containing the agent was prepared.

(Intermediate layer coating solution) Epoxy resin (Epicoat, Yuka-shell Co, Ltd.) 2 g Infrared absorbing agent (IR125 Wako Pure Chemical) 0.2 g 1-methoxy-2-propanol 9 g Methyl ethyl ketone 9 g

The surface of the support having the intermediate layer formed thereon was subjected to plasma treatment under the following conditions to form an image recording layer by surface graft polymerization. Using an LCVD-01 type plasma processing apparatus manufactured by Shimadzu Corporation under an argon gas atmosphere of 0.04 torr for 10 seconds, the substrate was exposed to air to introduce a peroxide group to the surface of the intermediate layer. This membrane was immersed in a 10 wt% aqueous solution of α (styrene-4-sulfonyl) acetate Na salt,
After bubbling argon gas for 5 minutes, graft polymerization was performed by heating to 60 ° C. for 7 hours. After the graft polymerization, the membrane was immersed in 3000 ml of ion-exchanged water, and the homopolymer other than the graft polymerization was removed to obtain an image forming material A having an image recording layer grafted on the surface by plasma treatment.

(Image Formation: Pattern Formation) The obtained image forming material A was exposed imagewise with an infrared laser (beam diameter: 20 μm) emitting infrared light having a wavelength of 830 nm. After exposure, the image forming material A is methylene blue (manufactured by Wako Pure Chemical Industries, Ltd.)
After being immersed in a 0.1% by weight aqueous solution for 10 minutes and washed with distilled water, methylene blue was selectively adhered imagewise to the infrared laser-exposed portion to form a clear blue image.

Example 2 (Image forming material: preparation of pattern forming material) 188 μm
Using a corona-treated biaxially stretched polyethylene terephthalate film (A4100, manufactured by Toyobo Co., Ltd.). Processing was performed.

Initial vacuum: 9 × 10 ⁶ ton Oxygen pressure: 6.8 × 10 ³ ton RF glow: 1.5 kw Processing time: 60 sec

Next, a solution of the following exemplified monomer (M-1) in methyl ethyl ketone (5
(0 wt%), dried at 100 ° C. for 1 minute, and irradiated with UV light (400 W high-pressure mercury lamp for 30 minutes) to perform graft polymerization to form a graft layer. Further, a 5% by weight acetonitrile solution of a light-to-heat converting dye (IR-A) having the following structure was applied with a rod bar # 7, and the light-to-heat converting dye was contained in the graft layer to obtain an image forming material B.

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Embedded image

(Image formation: pattern formation) The obtained image forming material B was exposed imagewise with an infrared laser (beam diameter: 20 μm) emitting infrared light having a wavelength of 830 nm. After exposure, image forming material B is methylene blue (manufactured by Wako Pure Chemical Industries, Ltd.)
After being immersed in a 0.1% by weight aqueous solution for 10 minutes and washed with distilled water, methylene blue was selectively adhered imagewise to the infrared laser-exposed portion to form a clear blue image.

[0076]

According to the image forming material of the present invention, an image can be formed with high sensitivity by exposure and heating, and a high resolution and high sharpness image can be obtained regardless of the area of the image forming material. In addition, by operating an infrared laser or the like, an excellent effect that an image can be directly formed on the basis of digital data is exhibited, and thus a wide range of applications is expected.

Claims (3)

[Claims] 1. A high molecular compound having a functional group whose hydrophilicity / hydrophobicity is changed by heat, acid or radiation on a support and having a structure capable of being directly bonded to the support by a chemical bond. Equipped with an image recording layer, the image recording layer can be heated, supplied with an acid, or irradiated with radiation to change the hydrophilicity / hydrophobicity of the surface of the image recording layer and form a visible image in the region where the hydrophilicity / hydrophobicity has changed. An image forming material characterized by adsorbing various organic or inorganic molecules. 2. A polymer compound having a functional group whose hydrophilicity / hydrophobicity changes by heat, acid or radiation and having a structure capable of being directly bonded to the support by a chemical bond,
A linear polymer compound directly bonded to the support surface by a chemical bond at the end of the polymer chain, or
2. The image forming material according to claim 1, wherein the image forming material is a linear polymer compound bonded to the surface of the support by a chemical bond at a terminal of the polymer chain via a trunk polymer compound. 3. The image forming material according to claim 1, wherein the organic or inorganic molecules capable of forming the visible image are selected from organic or inorganic dyes and pigments.